The present invention relates to the field of electrical utility usage mitigation and optimization, and to the field of distributed energy storage.
Electrical energy generation and distribution had been a mainstay for residential and commercial energy needs for societies all over the world for many years. Various forms of electrical energy generation have existed for some time now, including coal fired power plants, nuclear power plants, hydroelectric plants, wind harness plants, and others. All of these forms of electrical energy generation are well known to those of skill in the art of power generation and details of their operation need not be set forth herein. Many volumes of published literature exist on all of these well-known forms of electrical power generation, from sources all over the world.
As power generation has advanced, power usage has increased. This is due to many societal factors. First, populations in practically every country of the world have increased, resulting in more power needs. Second, consumer products frequently are designed to use electrical energy in order to operate. Due to advances in technology, more electronic products are available for use today than at any time in world history. Third, manufacturing plants have realized that machine automation can increase plant productivity and decrease production costs. Such automation usually requires electrical energy. Thus, the overall result is a greater need for electrical energy than ever before.
Another common occurrence around the world related to energy consumption is that consumption is greater during certain hours of the day. In any given time zone, electrical energy usage is greatest during hours of 6 a.m. and 10 p.m., commonly referred to as the “awake hours” or waking hours. Between 10 p.m. and 6 a.m. the next day, most people are sleeping and therefore are using less electrical energy. These hours are commonly called the “sleeping hours.” In order to avoid energy “brownouts” or, worse yet, “blackouts,” power companies have to be able to meet “peak demand” requirements of any given 24 hour day. These peak demand requirements occur during the awake hours and historical data obtained from tracking energy usage can fairly accurately predict how much energy will be needed each hour of each day in practically any community. Therefore, peak demand is one of the main drivers of the size and number of power plants needed for any given area. Peak demand drives the sizing and number of feeders, mains, transformers, and other power distribution elements in the grid as well.
The problem with using peak demand requirements to determine power plant capacity is that it does not make for efficient use of the resulting power plant. For example, if a peak demand period in a given area is X kilowatt-hours and that demand is only required for a period of eight hours each day, and the average demand for the rest of the day is half of X, then the design capacity of that power plant for the other sixteen hours of the day is not being effectively utilized. Said another way, if the full energy production capacity of each power plant, for each day, was utilized, fewer power plants would be needed because each one would be fully utilized, all day, every day. Design and usage could then be based on total energy needs each day rather than peak demand needs. Using peak demand requirements also results in an inefficient use of the distribution and transmission systems used by the power plants to deliver the electrical energy they produce.
Another problem with peak demand requirements is the high environmental and financial costs of operating the plants. The power plants that respond to peak demand loads during especially high demand periods of time are frequently more pollutive and expensive to operate than non-peaking power plants. The power companies operating the power plants that wait to supply power for peak demand periods charge a high price to local utilities for their temporary power output. Local utilities then pass the costs of buying power from these peak demand plants to customers as a “demand charge” based on the highest peak draw that the customer takes from the power grid over a billing period. Demand charges are determined differently by various utility providers but tend to be based on the highest usage of electricity (in kW) over a short period of time within a monthly billing cycle. Electricity providers justify these costs by citing the high prices of the peak demand power supply companies and by explaining that they must constantly upgrade and increase capacity of the distribution grid to manage the “spikes” in demand that arise during peak periods.
A consumer's draw on the power grid is, on average, much lower than the power level at which they are rated for demand charges. End users are often unaware of when or how demand charges are accumulated and are displeased to find out that their average electricity consumption is in fact typically much lower than these peaks, and that their power charges would be significantly reduced if their peaks in consumption could be mitigated or eliminated. Environmentally-conscious end users also seek to reduce emissions from the pollutive power plants that provide peaking energy to the grid by decreasing their reliance on them as a power source for peak energy needs.
Furthermore, utility providers have difficulty in estimating and confirming the amount of demand response that results when the providers broadcast a need for demand response participation from enrollees in a demand response program. Requests are traditionally sent out via telephone, and loads at the participants' sites must be manually curtailed by the customer. This can lead to actual participation rates that are much lower than enrollment logs would indicate.